<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <script src="./vue.js"></script>
    <style>
        .box{
            width:200px;
            height: 200px;
            background: rgb(228, 143, 143);
        }
    </style>
</head>
<body>
    <div id="app">
       <div v-bind:class="a"> 
        </div>
        <div v-bind:class=" 1>2?'box1':'box2' "> 
        </div>
        <div :class="a"> 
        </div>
        <div aa="10"></div>
    </div>
    <script>
        let vm = new Vue({
            el:"#app",
            data:{
                a:'box'
            }
        })
        
    </script>
</body>
</html>